This invention relates to an arrangement and method for the regulation of idle speed and charge pressure in a supercharged combustion engine.
1. Prior Art
In motor vehicles a lot of different regulating valves are used for regulation of, for example, the combustion engine of the motor vehicle. Due to different demands in aspects of accuracy and response and often need for simultaneous regulation with different orders of regulation demanded for the regulated functions in question, a large amount of different regulating valves are often necessitated. A typical regulating valve could be found in the inlet manifold of the engine, with the regulating valve being arranged in a shunt channel bypassing the throttle. This regulating valve is used for controlling the idle speed, and exhibits a very rapid response and accuracy in order to meet sudden changes in speed. These changes in speed could be induced by a sudden increase in load put upon the engine from different engine driven accessories such as air conditioning, generator, etc. Another typical regulating valve could be found in supercharged turbo engines, where a regulating valve known as a waste-gate is dumping excessive charge pressure. The waste-gate is preferably regulated by a pressure controlled diaphragm pot, pressurized from the inlet manifold of the engine in a regulated manner by a special regulating valve.
Both of the above mentioned regulating valves conventionally includes individual controls for regulation of respective regulating valve depending on different engine parameters.
2. Summary of the Invention
An object of the present invention is to reduce the number of regulating valves and controls for a supercharged combustion engine.
Another object is to obtain an improved regulation of the charge pressure in aspects of accuracy and response at a low cost.
In order to obtain these objects, the inventive arrangement includes a shunt channel connected to the inlet manifold of the engine to enable a throttle located in the inlet manifold to be by-passed. An idle speed valve is arranged in the shunt channel for selectively opening and closing the shunt channel. A selectively operable charge control regulating valve is provided for controlling the charge pressure in the inlet manifold, the charge pressure being a function of the degree of opening of the charge control valve. Pressure responsive means are provided for regulating the degree of opening of the charge control valve. A supply duct is connected between the shunt channel and the pressure responsive means for selectively supplying pressure to the pressure responsive means, the supply duct being connected to the shunt channel at a point downstream of the idle speed valve.
In accordance with the inventive method, the idle speed or charge pressure of a super-charged engine is regulated by deflecting air from the inlet manifold upstream of throttle to either a diaphragm pot used to control a regulating valve used to control charge pressure or to the inlet manifold downstream of the throttle.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.